Apparatus for generating steam



I E. P. MORITZ APPARATUS FOR GENERATING STEAM Oct. 21, 1930.

Filed Feb. '7, 1927 I INVENYV'IOR KU'ORNEYJ" TED OFFICE i ED'WIN P.URTTZ, 0F YORK, It. TI, ASSIGNOR T0 INTERNATIONAL COMBUSTIONGIENTSECRING CORPORATION, @ll NEW YORK, N. Y., A CORPORATION,OF DELAWAREill till! could not fill arr ATUS FOR GENERATING STEAM Application filedFebruary 7, 1927. Serial No. 166,289.

This invention relates to the art of generating steam, and toimprovements inoperation, especially in so far as combustionisconcerned. I 1

@ne of the primary objects of this invention istoefiectively burn ,blastfurnace gas I or other low grade gases in a radiant heat boiler. I

Another object of the invention has to do with improvements in efiectingcombustion at times of peak load in a radiant heat boiler of a size suchthat it can meet normaldemands while burning the fuel efficiently, butwhich in'the absence of such improvements, peak demands with efficiency.More specific objects will appear hereinafter. v

How the foregoing, together with such othor objects and advantages asmay hereinafter appear, or are incident to my invention, are realized,is illustrated in preferred form in the accompanying drawing, whereinThe figure is a sectional elevation of a boilor furnace embodying theinvention. 7

Referring now to the drawing, the reference character A denotes thecombustion chamber of the furnace which is largely defined by a frontwater wall 2., side water walls 3, and a rear water wall t. These'waterwalls are composed of upright tubes having longitudinally extending finswelded or otherwise secured thereto, the fins and tubes cooperating toform a practically continuousmetallic wall The top of the combustionspace is defined by the row of tubes 5 and the refractories 6, and thebottom is defined by a bank of tubes 7, the tubes of which are laterallyspaced apart sulficiently to permit the free passage of the wastegaseous products of combustion and of the descending refuse and fuel, ina manner well known in the art.

The tubes of the rear wall 4 have their upper and lower endsrespectively connected into upper and lower drums 8 and 9." The tubes ofthe side walls 3 have their upperand lower ends, respectively, connectedinto headers 10 and ll,in turn respectively connected into the drums 8and 9.- The tubes of the front wall 2 have their lower ends con admitgas, pulverized fuel and air nected into a drum 12, the drum 9 by thebank their upper ends connected into a drum or header 13 in turnconnected to the drum 8 bv the roof tubes 5.

Fuel is preferably admitted in the upper portion of the combustionchamber A at the four corners thereof by means of the burners indicatedas a whole by the reference numera1 14. These burners each comprise apluin turn connected to of tubes 7 and have A bit rality of gas nozzles15 and a plurality of pulverized fuel nozzles 16, the latter beingpreferably located between the former. Blast furnace gas is supplied tothe gas nozzles 15 from the gas main 1'2 and pulverized coal is suppliedto the nozzles 16 from the distributors 18. Combustion air is suppliedaround the burners by means of the channel 19 leading from the airpreheater B, with which is associated a forced draft fan B. Thus, itWill be seen that the burners are adapted to into the furnace in amanner to produce turbulent mixing. ln this connection, it is to benoted that by employing valves 38 and 39 controlling the admission ofthe ized fuel respectively, either may be; burned by shutting off theother. The air supply is common to both.

Bylocating the burners at the corners a vortical motion of thefuel andflame stream is set up, the axis of: the vortex being longitudinal ofthe boiler furnace. The fuel and flame'stream sweeps over the tubeswhich is ofimportance with low grade gas, as there is thus securedtransmission of heat both by radiation and by convection--v'vhich isespecially desirable because of the flame of low grade gas does not havea high capacity for transmitting heat by radiation.

The pulverized coal admitted with the gas will add luminosity to theflame, and thus increase its radiating capacity. Therefore, medium, andespecially at high, ratings, .l burn pulverized coal with the gassecuring an increase in the transmission of heat by radiation, as wellas by convection to give the increased capacity desired, and which otherwise could not be obtained in a radiant heat gas and the pulver- "illtill

boiler by merely increasing quantity or gas admitted.

The evaporating area of the boiler is such as to supply normal demandswhen operating efficiently from the standpoint of combustion to whichend the air admission at the burners and at 20 is adequate toefficiently burn the quantities of fuel admitted to supply normaldemands. To make such a boiler supply peak of air in the space definedby the boiler to increase the temperature and, therefore, the rate ofheat transmission.

Under these conditions, some combustibles tend to pass out with thewaste products of combustion, which combustibles I propose to burn in asecondary chamber C located beyond the bank of tubes 7, into which isintroduced the additional amount of air required for combustion.

As a means for introducing this secondary 7' air, I have provided ametallic air box or over the superheater 26 which channel 21 covered byrefractories 22, the front wall of which has a plurality of air ports 23controlled by damper 37 for admitting air into the chamber C in adirection toward the front wall of the furnace. In this instance,preheated air is led to the channel 21 by means of the branch conduit 24of the air channel 19. In this connection, is pointed out that thesecondary air, flowing as it does in a direction substantially oppositeto that of the path of flow of the products of combustion, tends tomaintain the products of combustion away from the refractories of thechannel 21 so that they are protected as against scouring.

The waste gasesfrom the chamber G pass rearwardly and upwardly over thebank of economizer tubes 25, the upper and lower ends of which areconnected into the upper and lower drums 8 and 9, respectively, and islocated amongst the economizer tubes. It will be noted that thearrangement is such that the economizer tubes become the downcomers ofthe boiler. I

Reverting now to the air channel 21, it will be observed that the air isadmitted to the chamber C in such mannerthat thorough mixing takes placein the fore part of such chamberthus ensuring completion of combustionbefore the economizer and superheater are reached.

The rear pass of the boiler in which the economizer section andsuperheater is located is defined by a rear refractory wall 27 forwardlyoffset at 28 and having vertically spaced transversely extendingprojections 29, and by the refractory sheathing 30 having a projection31, similar to the projections 29,

located at an elevation intermediate the elevations of the projections29. By means of these bafiles, the products are forced to take a more orless tortuous path through the econdemands, I operate it with adeficiency omizer section and superheater unit until they finally emergeinto the breeching 32 from which they are carried to the stack 33 by theaction of the induced draft fan 34:.

The location in the ofltalre of the conomizer section,- the superheaterand the air heater ensures the absorption of heat from the waste gaseswhereby the final exit temperatures are kept within allowable limits.

Owing to the character of the fuel being burned I have provided an ashpit 35 of considerable size. A plurality of gate controlled openings 36are provided in the bottom of the ash pit for removing from time to timethe refuse and ash collecting therein. The gates are normally closedwhen the furnace is functioning as diagrammatically indicated in thedrawing.

From the foregoing it will be seen that the arrangement of the furnaceand associated parts is such that considerably less floor space and headroom is required than heretofore. The arrangement is well adapted to thegrouping of a plurality of boiler units in a small area.

In comparison to other arrangements for the burning of low grade fuels,such as blast furnace gas, a relatively high ca acity for a relativelysmall sized boiler is o tained.

It claim 1. In combination, a tubular boiler furnace comprising aplurality of vertically extending water tubes defining the rear, frontand side walls of the combustion chamber of the furnace, means forintroducting and lnirning pulverized coal and gas in said combustionchamber, a secondary combustion chamber. an air channel below the rearwall of said first combustion chamber, and means associated with saidchannel for introducing an ad ditional supply of air into said secondarycombustion chamber and economizer elements subject to the heat of saidsecondary combustion and associated with the boiler-furnace so that theheat absorbed is utilized in the generation of the steam.

2. In combination, a tubular boiler furnace comprising a plurality ofvertically-extending water tubes defining the major portion of the wallsof the combustion chamber of the furnace, means for introducingpulverized, fuel and gasinto said combustion chamber, means forsupplying combustion air, a cross drum into which the lower ends of therear water tubes are connected, an air channel disposed beneath saidcross drum, means associated with said channel for introducing aregulated amount of air into the furnace below the combustion chamberthereof for promoting complete secondary combustion of the fuel, andeconomizer elements subject to the heat of said secondary combustion andassociated with the boiler-furnace so that the heat absorbed is utilizedin the generation of the steam.

'subject'to the gaseous products of combustion in said offtake, saidelements being associated with the boiler-furnace so that the heatabsorbed thereby is utilized in the generation of the steam. v

In testimony whereof I have hereunto signed my name.

. EDWIN P. MORITZ.

